Howard Wolfson, a spokesman for Clinton, referred to a passage in the book which referred to one part of her Bosnia trip being cut short by threats of sniper fire, as the passage she was mistakenly referring to.

"That is what she wrote in her book ... that is what she has said many, many times and on one occasion she misspoke."

However a spokesman for Barack Obama, the Illinois senator and Clinton's rival for the Democratic presidential nomination, said the incident was "not misspeaking, it's misleading".

"[This] joins a growing list of instances in which Senator Clinton hasexaggerated her role in foreign and domestic policymaking," he said.

The two senators are locked in a bitter contest for the Democratic nomination, with the two increasingly sparring ahead of the next primary vote in Pennsylvania on April 22.

Obama holds a consistent lead in the race's delegate count, and earlier this week won the backing of Bill Richardson, the Hispanic governor of the US state of New Mexico.

However he has seen his lead in national polls dip in recent weeks after controversial remarks by his former pastor surfaced in the US media.